Electrocoagulation and nanofiltration integrated process application in purification of bilge water using response surface methodology

Marine pollution has been considered an increasing problem because of the increase in sea transportation day by day. Therefore, a large volume of bilge water which contains petroleum, oil and hydrocarbons in high concentrations is generated from all types of ships. In this study, treatment of bilge water by electrocoagulation/electroflotation and nanofiltration integrated process is investigated as a function of voltage, time, and initial pH with aluminum electrode as both anode and cathode. Moreover, a commercial NF270 flat-sheet membrane was also used for further purification. Box–Behnken design combined with response surface methodology was used to study the response pattern and determine the optimum conditions for maximum chemical oxygen demand (COD) removal and minimum metal ion contents of bilge water. Three independent variables, namely voltage (5–15 V), initial pH (4.5–8.0) and time (30–90 min) were transformed to coded values. The COD removal percent, UV absorbance at 254 nm, pH value (after treatment), and concentration of metal ions (Ti, As, Cu, Cr, Zn, Sr, Mo) were obtained as responses. Analysis of variance results showed that all the models were significant except for Zn (P > 0.05), because the calculated F values for these models were less than the critical F value for the considered probability (P = 0.05). The obtained R2 and Radj2 values signified the correlation between the experimental data and predicted responses: except for the model of Zn concentration after treatment, the high R2 values showed the goodness of fit of the model. While the increase in the applied voltage showed negative effects, the increases in time and pH showed a positive effect on COD removal efficiency; also the most effective linear term was found as time. A positive sign of the interactive coefficients of the voltage–time and pH–time systems indicated synergistic effect on COD removal efficiency, whereas interaction between voltage and pH showed an antagonistic effect.

Related articles

The Situation
Various processes onboard ships, such as machinery wash-down, maintenance, and leakage, generate oily wastewater. This contaminated water flow collects in the bilge of the ship. Marine diesel, lubricating oils, grease, as well as other contaminants may be present in bilge water. The bilge water is discharged overboard, with oil and grease concentrations in the discharged water limited by national and international regulations.In the United States territorial waters, the U.S. Coast Guard (USCG)...

Applications for industrial oil in water monitoring can vary greatly.
In upstream and midstream oil and gas production applications, monitoring separation efficiencies is key to optimize production rates, preventative maintenance, chemical use, flow, and environmental compliance. Separated water from the oil is called produced water and it must be cleaned of oil before disposal or re-injection.
In downstream applications and for end-users of fuels and oils, environmental compliance becomes key for stormwater...

The study was undertaken for Crowley Shipping Company, managers for reduced Operational ships or ROSS ships to evaluate BilgeRemed for complete reduction of oil in the oily bilge water. The oily bilge water in these ships is collected by contracted trucks who transport the bilge water for off-site disposal and is generally a very expensive operation. In a cost cutting effort a study on effect of BilgeRemed on the oily bilge water was carried out on one such ship M/V Cape Wrath for five weeks. BilgeRemed for the...

Ship board studies on effect of BilgeRemed on oily bilge water in sea going ships was carried out on a ship operating from Port Kitimat, BC in Canada. 5 gallons of BilgeRemed was added on a weekly basis to the oily bilge water holding tank after collecting a airlifting sample of oily bilge water for analysis to SARVA. The results show that the Total Petroleum Hydrocarbons (TPH) of the water was reduced from 19,000 ppm to 5.0 ppm in 3 weeks and the water discharged from the OWS was very clear and it met the...

The Situation
Various processes onboard ships, such as machinery wash-down, maintenance, and leakage generate oily wastewater. This contaminated water flow collects in the bilge of the ship. Marine diesel, lubricating oils, grease, as well as garbage may be present in bilge water. The bilge water is discharged overboard, with oil and grease concentrations in the discharged water limited by national and international regulations.
In the United States territorial waters, the U.S. Coast Guard (USCG) limits the...

Customer comments

No comments were found for Electrocoagulation and nanofiltration integrated process application in purification of bilge water using response surface methodology. Be the first to comment!

Add your comment

Great! comment successfully added!

Contact

Your message:

Your email

Your first name

Your last name

I would like to receive periodic email updates and special offers from select suppliers.